Obesity at age 20 and weight gain during adulthood increase risk of total and premature all-cause mortality: findings from women attending breast screening in Manchester

Table 2 Death rates by BMI category and BMI change category

	N	All deaths			Premature deaths
	N	Length of follow up (person years)	Deaths (n)	Death rate per 1000 (95% CI)	Length of follow up (person years)^a	Deaths (n)	Death rate per 1000 (95% CI)
BMI category age 20
Underweight	3606	31,191.08	127	4.07 (3.41–4.83)	29,073.83	105	3.61 (2.70–4.35)
Healthy weight	38,720	336,317.58	1 382	4.11 (3.90–4.33)	312,590.58	1 158	3.71 (3.50–3.92)
Overweight	5032	43,476.08	243	5.59 (4.92–6.33)	40,525.17	202	4.99 (4.33–5.72)
Obese	1222	10,374.42	89	8.58 (6.93–10.51)	9744.00	81	8.31 (6.65–10.28)
BMI change category^b
Underweight or healthy weight → underweight or healthy weight	18,300	158,569.33	590	3.72 (3.43–4.03)	148,284.83	495	3.34 (3.05–3.64)
Underweight or healthy weight → overweight	15,607	135,874.42	544	4.00 (3.68–4.35)	125,596.33	451	3.59 (3.27–3.93)
Underweight or healthy weight → obese	8419	73,064.92	375	5.13 (4.63–5.67)	67,792.58	317	4.68 (4.18–5.21)
Overweight → underweight or healthy weight	525	4554.33	34	7.47 (5.25–10.31)	4200.92	30	7.14 (4.91–10.07)
Overweight → overweight	1304	11,287.67	68	6.02 (4.72–7.59)	10,347.25	51	4.93 (3.71–6.43)
Overweight → obese	3203	27,634.08	141	5.10 (4.31–6.00)	25,967.67	121	4.66 (3.88–5.55)
Obese → underweight or healthy weight	60	522.67	13	24.87 (13.83–41.46)	440.92	11	24.95 (13.12–43.36)
Obese → overweight	187	1596.33	16	10.02 (5.93–15.93)	1495.33	15	10.03 (0.58–1.62)
Obese → obese	975	8255.42	60	7.27 (5.60–9.29)	7807.75	55	7.04 (5.36–9.10)
Overall group	48,580	421,359.17	1841	4.37 (4.17–4.57)	391,933.58	1546	3.95 (3.75–4.15)

^aFrom PROCAS entry to earliest of death, age if < 75 at time of censor, or age 75
^bDue to low numbers of women underweight at entry and the focus of the analyses on obesity, the underweight and healthy weight categories were combined

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